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 <head>
  <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
  <meta content="width=device-width, initial-scale=1, shrink-to-fit=no" name="viewport">
  <title>WebXR Meshing API Level 1</title>
<style data-fill-with="stylesheet">/******************************************************************************
 *                   Style sheet for the W3C specifications                   *
 *
 * Special classes handled by this style sheet include:
 *
 * Indices
 *   - .toc for the Table of Contents (<ol class="toc">)
 *     + <span class="secno"> for the section numbers
 *   - #toc for the Table of Contents (<nav id="toc">)
 *   - ul.index for Indices (<a href="#ref">term</a><span>, in §N.M</span>)
 *   - table.index for Index Tables (e.g. for properties or elements)
 *
 * Structural Markup
 *   - table.data for general data tables
 *     -> use 'scope' attribute, <colgroup>, <thead>, and <tbody> for best results !
 *     -> use <table class='complex data'> for extra-complex tables
 *     -> use <td class='long'> for paragraph-length cell content
 *     -> use <td class='pre'> when manual line breaks/indentation would help readability
 *   - dl.switch for switch statements
 *   - ol.algorithm for algorithms (helps to visualize nesting)
 *   - .figure and .caption (HTML4) and figure and figcaption (HTML5)
 *     -> .sidefigure for right-floated figures
 *   - ins/del
 *
 * Code
 *   - pre and code
 *
 * Special Sections
 *   - .note       for informative notes             (div, p, span, aside, details)
 *   - .example    for informative examples          (div, p, pre, span)
 *   - .issue      for issues                        (div, p, span)
 *   - .assertion  for assertions                    (div, p, span)
 *   - .advisement for loud normative statements     (div, p, strong)
 *   - .annoying-warning for spec obsoletion notices (div, aside, details)
 *
 * Definition Boxes
 *   - pre.def   for WebIDL definitions
 *   - table.def for tables that define other entities (e.g. CSS properties)
 *   - dl.def    for definition lists that define other entitles (e.g. HTML elements)
 *
 * Numbering
 *   - .secno for section numbers in .toc and headings (<span class='secno'>3.2</span>)
 *   - .marker for source-inserted example/figure/issue numbers (<span class='marker'>Issue 4</span>)
 *   - ::before styled for CSS-generated issue/example/figure numbers:
 *     -> Documents wishing to use this only need to add
 *        figcaption::before,
 *        .caption::before { content: "Figure "  counter(figure) " ";  }
 *        .example::before { content: "Example " counter(example) " "; }
 *        .issue::before   { content: "Issue "   counter(issue) " ";   }
 *
 * Header Stuff (ignore, just don't conflict with these classes)
 *   - .head for the header
 *   - .copyright for the copyright
 *
 * Miscellaneous
 *   - .overlarge for things that should be as wide as possible, even if
 *     that overflows the body text area. This can be used on an item or
 *     on its container, depending on the effect desired.
 *     Note that this styling basically doesn't help at all when printing,
 *     since A4 paper isn't much wider than the max-width here.
 *     It's better to design things to fit into a narrower measure if possible.
 *   - js-added ToC jump links (see fixup.js)
 *
 ******************************************************************************/

/******************************************************************************/
/*                                   Body                                     */
/******************************************************************************/

	body {
		counter-reset: example figure issue;

		/* Layout */
		max-width: 50em;               /* limit line length to 50em for readability   */
		margin: 0 auto;                /* center text within page                     */
		padding: 1.6em 1.5em 2em 50px; /* assume 16px font size for downlevel clients */
		padding: 1.6em 1.5em 2em calc(26px + 1.5em); /* leave space for status flag     */

		/* Typography */
		line-height: 1.5;
		font-family: sans-serif;
		widows: 2;
		orphans: 2;
		word-wrap: break-word;
		overflow-wrap: break-word;
		hyphens: auto;

		/* Colors */
		color: black;
		background: white top left fixed no-repeat;
		background-size: 25px auto;
	}


/******************************************************************************/
/*                         Front Matter & Navigation                          */
/******************************************************************************/

/** Header ********************************************************************/

	div.head { margin-bottom: 1em }
	div.head hr { border-style: solid; }

	div.head h1 {
		font-weight: bold;
		margin: 0 0 .1em;
		font-size: 220%;
	}

	div.head h2 { margin-bottom: 1.5em;}

/** W3C Logo ******************************************************************/

	.head .logo {
		float: right;
		margin: 0.4rem 0 0.2rem .4rem;
	}

	.head img[src*="logos/W3C"] {
		display: block;
		border: solid #1a5e9a;
		border-width: .65rem .7rem .6rem;
		border-radius: .4rem;
		background: #1a5e9a;
		color: white;
		font-weight: bold;
	}

	.head a:hover > img[src*="logos/W3C"],
	.head a:focus > img[src*="logos/W3C"] {
		opacity: .8;
	}

	.head a:active > img[src*="logos/W3C"] {
		background: #c00;
		border-color: #c00;
	}

	/* see also additional rules in Link Styling section */

/** Copyright *****************************************************************/

	p.copyright,
	p.copyright small { font-size: small }

/** Back to Top / ToC Toggle **************************************************/

	@media print {
		#toc-nav {
			display: none;
		}
	}
	@media not print {
		#toc-nav {
			position: fixed;
			z-index: 2;
			bottom: 0; left: 0;
			margin: 0;
			min-width: 1.33em;
			border-top-right-radius: 2rem;
			box-shadow: 0 0 2px;
			font-size: 1.5em;
			color: black;
		}
		#toc-nav > a {
			display: block;
			white-space: nowrap;

			height: 1.33em;
			padding: .1em 0.3em;
			margin: 0;

			background: white;
			box-shadow: 0 0 2px;
			border: none;
			border-top-right-radius: 1.33em;
			background: white;
		}
		#toc-nav > #toc-jump {
			padding-bottom: 2em;
			margin-bottom: -1.9em;
		}

		#toc-nav > a:hover,
		#toc-nav > a:focus {
			background: #f8f8f8;
		}
		#toc-nav > a:not(:hover):not(:focus) {
			color: #707070;
		}

		/* statusbar gets in the way on keyboard focus; remove once browsers fix */
		#toc-nav > a[href="#toc"]:not(:hover):focus:last-child {
			padding-bottom: 1.5rem;
		}

		#toc-nav:not(:hover) > a:not(:focus) > span + span {
			/* Ideally this uses :focus-within on #toc-nav */
			display: none;
		}
		#toc-nav > a > span + span {
			padding-right: 0.2em;
		}

		#toc-toggle-inline {
			vertical-align: 0.05em;
			font-size: 80%;
			color: gray;
			color: hsla(203,20%,40%,.7);
			border-style: none;
			background: transparent;
			position: relative;
		}
		#toc-toggle-inline:hover:not(:active),
		#toc-toggle-inline:focus:not(:active) {
			text-shadow: 1px 1px silver;
			top: -1px;
			left: -1px;
		}

		#toc-nav :active {
			color: #C00;
		}
	}

/** ToC Sidebar ***************************************************************/

	/* Floating sidebar */
	@media screen {
		body.toc-sidebar #toc {
			position: fixed;
			top: 0; bottom: 0;
			left: 0;
			width: 23.5em;
			max-width: 80%;
			max-width: calc(100% - 2em - 26px);
			overflow: auto;
			padding: 0 1em;
			padding-left: 42px;
			padding-left: calc(1em + 26px);
			background: inherit;
			background-color: #f7f8f9;
			z-index: 1;
			box-shadow: -.1em 0 .25em rgba(0,0,0,.1) inset;
		}
		body.toc-sidebar #toc h2 {
			margin-top: .8rem;
			font-variant: small-caps;
			font-variant: all-small-caps;
			text-transform: lowercase;
			font-weight: bold;
			color: gray;
			color: hsla(203,20%,40%,.7);
		}
		body.toc-sidebar #toc-jump:not(:focus) {
			width: 0;
			height: 0;
			padding: 0;
			position: absolute;
			overflow: hidden;
		}
	}
	/* Hide main scroller when only the ToC is visible anyway */
	@media screen and (max-width: 28em) {
		body.toc-sidebar {
			overflow: hidden;
		}
	}

	/* Sidebar with its own space */
	@media screen and (min-width: 78em) {
		body:not(.toc-inline) #toc {
			position: fixed;
			top: 0; bottom: 0;
			left: 0;
			width: 23.5em;
			overflow: auto;
			padding: 0 1em;
			padding-left: 42px;
			padding-left: calc(1em + 26px);
			background: inherit;
			background-color: #f7f8f9;
			z-index: 1;
			box-shadow: -.1em 0 .25em rgba(0,0,0,.1) inset;
		}
		body:not(.toc-inline) #toc h2 {
			margin-top: .8rem;
			font-variant: small-caps;
			font-variant: all-small-caps;
			text-transform: lowercase;
			font-weight: bold;
			color: gray;
			color: hsla(203,20%,40%,.7);
		}

		body:not(.toc-inline) {
			padding-left: 29em;
		}
		/* See also Overflow section at the bottom */

		body:not(.toc-inline) #toc-jump:not(:focus) {
			width: 0;
			height: 0;
			padding: 0;
			position: absolute;
			overflow: hidden;
		}
	}
	@media screen and (min-width: 90em) {
		body:not(.toc-inline) {
			margin: 0 4em;
		}
	}

/******************************************************************************/
/*                                Sectioning                                  */
/******************************************************************************/

/** Headings ******************************************************************/

	h1, h2, h3, h4, h5, h6, dt {
		page-break-after: avoid;
		page-break-inside: avoid;
		font: 100% sans-serif;   /* Reset all font styling to clear out UA styles */
		font-family: inherit;    /* Inherit the font family. */
		line-height: 1.2;        /* Keep wrapped headings compact */
		hyphens: manual;         /* Hyphenated headings look weird */
	}

	h2, h3, h4, h5, h6 {
		margin-top: 3rem;
	}

	h1, h2, h3 {
		color: #005A9C;
		background: transparent;
	}

	h1 { font-size: 170%; }
	h2 { font-size: 140%; }
	h3 { font-size: 120%; }
	h4 { font-weight: bold; }
	h5 { font-style: italic; }
	h6 { font-variant: small-caps; }
	dt { font-weight: bold; }

/** Subheadings ***************************************************************/

	h1 + h2,
	#subtitle {
		/* #subtitle is a subtitle in an H2 under the H1 */
		margin-top: 0;
	}
	h2 + h3,
	h3 + h4,
	h4 + h5,
	h5 + h6 {
		margin-top: 1.2em; /* = 1 x line-height */
	}

/** Section divider ***********************************************************/

	:not(.head) > hr {
		font-size: 1.5em;
		text-align: center;
		margin: 1em auto;
		height: auto;
		border: transparent solid 0;
		background: transparent;
	}
	:not(.head) > hr::before {
		content: "\2727\2003\2003\2727\2003\2003\2727";
	}

/******************************************************************************/
/*                            Paragraphs and Lists                            */
/******************************************************************************/

	p {
		margin: 1em 0;
	}

	dd > p:first-child,
	li > p:first-child {
		margin-top: 0;
	}

	ul, ol {
		margin-left: 0;
		padding-left: 2em;
	}

	li {
		margin: 0.25em 0 0.5em;
		padding: 0;
	}

	dl dd {
		margin: 0 0 .5em 2em;
	}

	.head dd + dd { /* compact for header */
		margin-top: -.5em;
	}

	/* Style for algorithms */
	ol.algorithm ol:not(.algorithm),
	.algorithm > ol ol:not(.algorithm) {
	 border-left: 0.5em solid #DEF;
	}

	/* Put nice boxes around each algorithm. */
	[data-algorithm]:not(.heading) {
	  padding: .5em;
	  border: thin solid #ddd; border-radius: .5em;
	  margin: .5em calc(-0.5em - 1px);
	}
	[data-algorithm]:not(.heading) > :first-child {
	  margin-top: 0;
	}
	[data-algorithm]:not(.heading) > :last-child {
	  margin-bottom: 0;
	}

	/* Style for switch/case <dl>s */
	dl.switch > dd > ol.only,
	dl.switch > dd > .only > ol {
	 margin-left: 0;
	}
	dl.switch > dd > ol.algorithm,
	dl.switch > dd > .algorithm > ol {
	 margin-left: -2em;
	}
	dl.switch {
	 padding-left: 2em;
	}
	dl.switch > dt {
	 text-indent: -1.5em;
	 margin-top: 1em;
	}
	dl.switch > dt + dt {
	 margin-top: 0;
	}
	dl.switch > dt::before {
	 content: '\21AA';
	 padding: 0 0.5em 0 0;
	 display: inline-block;
	 width: 1em;
	 text-align: right;
	 line-height: 0.5em;
	}

/** Terminology Markup ********************************************************/


/******************************************************************************/
/*                                 Inline Markup                              */
/******************************************************************************/

/** Terminology Markup ********************************************************/
	dfn   { /* Defining instance */
		font-weight: bolder;
	}
	a > i { /* Instance of term */
		font-style: normal;
	}
	dt dfn code, code.idl {
		font-size: medium;
	}
	dfn var {
		font-style: normal;
	}

/** Change Marking ************************************************************/

	del { color: red;  text-decoration: line-through; }
	ins { color: #080; text-decoration: underline;    }

/** Miscellaneous improvements to inline formatting ***************************/

	sup {
		vertical-align: super;
		font-size: 80%
	}

/******************************************************************************/
/*                                    Code                                    */
/******************************************************************************/

/** General monospace/pre rules ***********************************************/

	pre, code, samp {
		font-family: Menlo, Consolas, "DejaVu Sans Mono", Monaco, monospace;
		font-size: .9em;
		page-break-inside: avoid;
		hyphens: none;
		text-transform: none;
	}
	pre code,
	code code {
		font-size: 100%;
	}

	pre {
		margin-top: 1em;
		margin-bottom: 1em;
		overflow: auto;
	}

/** Inline Code fragments *****************************************************/

  /* Do something nice. */

/******************************************************************************/
/*                                    Links                                   */
/******************************************************************************/

/** General Hyperlinks ********************************************************/

	/* We hyperlink a lot, so make it less intrusive */
	a[href] {
		color: #034575;
		text-decoration: none;
		border-bottom: 1px solid #707070;
		/* Need a bit of extending for it to look okay */
		padding: 0 1px 0;
		margin: 0 -1px 0;
	}
	a:visited {
		border-bottom-color: #BBB;
	}

	/* Use distinguishing colors when user is interacting with the link */
	a[href]:focus,
	a[href]:hover {
		background: #f8f8f8;
		background: rgba(75%, 75%, 75%, .25);
		border-bottom-width: 3px;
		margin-bottom: -2px;
	}
	a[href]:active {
		color: #C00;
		border-color: #C00;
	}

	/* Backout above styling for W3C logo */
	.head .logo,
	.head .logo a {
		border: none;
		text-decoration: none;
		background: transparent;
	}

/******************************************************************************/
/*                                    Images                                  */
/******************************************************************************/

	img {
		border-style: none;
	}

	/* For autogen numbers, add
	   .caption::before, figcaption::before { content: "Figure " counter(figure) ". "; }
	*/

	figure, .figure, .sidefigure {
		page-break-inside: avoid;
		text-align: center;
		margin: 2.5em 0;
	}
	.figure img,    .sidefigure img,    figure img,
	.figure object, .sidefigure object, figure object {
		max-width: 100%;
		margin: auto;
	}
	.figure pre, .sidefigure pre, figure pre {
		text-align: left;
		display: table;
		margin: 1em auto;
	}
	.figure table, figure table {
		margin: auto;
	}
	@media screen and (min-width: 20em) {
		.sidefigure {
			float: right;
			width: 50%;
			margin: 0 0 0.5em 0.5em
		}
	}
	.caption, figcaption, caption {
		font-style: italic;
		font-size: 90%;
	}
	.caption::before, figcaption::before, figcaption > .marker {
		font-weight: bold;
	}
	.caption, figcaption {
		counter-increment: figure;
	}

	/* DL list is indented 2em, but figure inside it is not */
	dd > .figure, dd > figure { margin-left: -2em }

/******************************************************************************/
/*                             Colored Boxes                                  */
/******************************************************************************/

	.issue, .note, .example, .assertion, .advisement, blockquote {
		padding: .5em;
		border: .5em;
		border-left-style: solid;
		page-break-inside: avoid;
	}
	span.issue, span.note {
		padding: .1em .5em .15em;
		border-right-style: solid;
	}

	.issue,
	.note,
	.example,
	.advisement,
	.assertion,
	blockquote {
		margin: 1em auto;
	}
	.note  > p:first-child,
	.issue > p:first-child,
	blockquote > :first-child {
		margin-top: 0;
	}
	blockquote > :last-child {
		margin-bottom: 0;
	}

/** Blockquotes ***************************************************************/

	blockquote {
		border-color: silver;
	}

/** Open issue ****************************************************************/

	.issue {
		border-color: #E05252;
		background: #FBE9E9;
		counter-increment: issue;
		overflow: auto;
	}
	.issue::before, .issue > .marker {
		text-transform: uppercase;
		color: #AE1E1E;
		padding-right: 1em;
		text-transform: uppercase;
	}
	/* Add .issue::before { content: "Issue " counter(issue) " "; } for autogen numbers,
	   or use class="marker" to mark up the issue number in source. */

/** Example *******************************************************************/

	.example {
		border-color: #E0CB52;
		background: #FCFAEE;
		counter-increment: example;
		overflow: auto;
		clear: both;
	}
	.example::before, .example > .marker {
		text-transform: uppercase;
		color: #827017;
		min-width: 7.5em;
		display: block;
	}
	/* Add .example::before { content: "Example " counter(example) " "; } for autogen numbers,
	   or use class="marker" to mark up the example number in source. */

/** Non-normative Note ********************************************************/

	.note {
		border-color: #52E052;
		background: #E9FBE9;
		overflow: auto;
	}

	.note::before, .note > .marker,
	details.note > summary::before,
	details.note > summary > .marker {
		text-transform: uppercase;
		display: block;
		color: hsl(120, 70%, 30%);
	}
	/* Add .note::before { content: "Note"; } for autogen label,
	   or use class="marker" to mark up the label in source. */

	details.note > summary {
		display: block;
		color: hsl(120, 70%, 30%);
	}
	details.note[open] > summary {
		border-bottom: 1px silver solid;
	}

/** Assertion Box *************************************************************/
	/*  for assertions in algorithms */

	.assertion {
		border-color: #AAA;
		background: #EEE;
	}

/** Advisement Box ************************************************************/
	/*  for attention-grabbing normative statements */

	.advisement {
		border-color: orange;
		border-style: none solid;
		background: #FFEECC;
	}
	strong.advisement {
		display: block;
		text-align: center;
	}
	.advisement > .marker {
		color: #B35F00;
	}

/** Spec Obsoletion Notice ****************************************************/
	/* obnoxious obsoletion notice for older/abandoned specs. */

	details {
		display: block;
	}
	summary {
		font-weight: bolder;
	}

	.annoying-warning:not(details),
	details.annoying-warning:not([open]) > summary,
	details.annoying-warning[open] {
		background: #fdd;
		color: red;
		font-weight: bold;
		padding: .75em 1em;
		border: thick red;
		border-style: solid;
		border-radius: 1em;
	}
	.annoying-warning :last-child {
		margin-bottom: 0;
	}

@media not print {
	details.annoying-warning[open] {
		position: fixed;
		left: 1em;
		right: 1em;
		bottom: 1em;
		z-index: 1000;
	}
}

	details.annoying-warning:not([open]) > summary {
		text-align: center;
	}

/** Entity Definition Boxes ***************************************************/

	.def {
		padding: .5em 1em;
		background: #DEF;
		margin: 1.2em 0;
		border-left: 0.5em solid #8CCBF2;
	}

/******************************************************************************/
/*                                    Tables                                  */
/******************************************************************************/

	th, td {
		text-align: left;
		text-align: start;
	}

/** Property/Descriptor Definition Tables *************************************/

	table.def {
		/* inherits .def box styling, see above */
		width: 100%;
		border-spacing: 0;
	}

	table.def td,
	table.def th {
		padding: 0.5em;
		vertical-align: baseline;
		border-bottom: 1px solid #bbd7e9;
	}

	table.def > tbody > tr:last-child th,
	table.def > tbody > tr:last-child td {
		border-bottom: 0;
	}

	table.def th {
		font-style: italic;
		font-weight: normal;
		padding-left: 1em;
		width: 3em;
	}

	/* For when values are extra-complex and need formatting for readability */
	table td.pre {
		white-space: pre-wrap;
	}

	/* A footnote at the bottom of a def table */
	table.def           td.footnote {
		padding-top: 0.6em;
	}
	table.def           td.footnote::before {
		content: " ";
		display: block;
		height: 0.6em;
		width: 4em;
		border-top: thin solid;
	}

/** Data tables (and properly marked-up index tables) *************************/
	/*
		 <table class="data"> highlights structural relationships in a table
		 when correct markup is used (e.g. thead/tbody, th vs. td, scope attribute)

		 Use class="complex data" for particularly complicated tables --
		 (This will draw more lines: busier, but clearer.)

		 Use class="long" on table cells with paragraph-like contents
		 (This will adjust text alignment accordingly.)
		 Alternately use class="longlastcol" on tables, to have the last column assume "long".
	*/

	table {
		word-wrap: normal;
		overflow-wrap: normal;
		hyphens: manual;
	}

	table.data,
	table.index {
		margin: 1em auto;
		border-collapse: collapse;
		border: hidden;
		width: 100%;
	}
	table.data caption,
	table.index caption {
		max-width: 50em;
		margin: 0 auto 1em;
	}

	table.data td,  table.data th,
	table.index td, table.index th {
		padding: 0.5em 1em;
		border-width: 1px;
		border-color: silver;
		border-top-style: solid;
	}

	table.data thead td:empty {
		padding: 0;
		border: 0;
	}

	table.data  thead,
	table.index thead,
	table.data  tbody,
	table.index tbody {
		border-bottom: 2px solid;
	}

	table.data colgroup,
	table.index colgroup {
		border-left: 2px solid;
	}

	table.data  tbody th:first-child,
	table.index tbody th:first-child  {
		border-right: 2px solid;
		border-top: 1px solid silver;
		padding-right: 1em;
	}

	table.data th[colspan],
	table.data td[colspan] {
		text-align: center;
	}

	table.complex.data th,
	table.complex.data td {
		border: 1px solid silver;
		text-align: center;
	}

	table.data.longlastcol td:last-child,
	table.data td.long {
	 vertical-align: baseline;
	 text-align: left;
	}

	table.data img {
		vertical-align: middle;
	}


/*
Alternate table alignment rules

	table.data,
	table.index {
		text-align: center;
	}

	table.data  thead th[scope="row"],
	table.index thead th[scope="row"] {
		text-align: right;
	}

	table.data  tbody th:first-child,
	table.index tbody th:first-child  {
		text-align: right;
	}

Possible extra rowspan handling

	table.data  tbody th[rowspan]:not([rowspan='1']),
	table.index tbody th[rowspan]:not([rowspan='1']),
	table.data  tbody td[rowspan]:not([rowspan='1']),
	table.index tbody td[rowspan]:not([rowspan='1']) {
		border-left: 1px solid silver;
	}

	table.data  tbody th[rowspan]:first-child,
	table.index tbody th[rowspan]:first-child,
	table.data  tbody td[rowspan]:first-child,
	table.index tbody td[rowspan]:first-child{
		border-left: 0;
		border-right: 1px solid silver;
	}
*/

/******************************************************************************/
/*                                  Indices                                   */
/******************************************************************************/


/** Table of Contents *********************************************************/

	.toc a {
		/* More spacing; use padding to make it part of the click target. */
		padding-top: 0.1rem;
		/* Larger, more consistently-sized click target */
		display: block;
		/* Reverse color scheme */
		color: black;
		border-color: #3980B5;
		border-bottom-width: 3px !important;
		margin-bottom: 0px !important;
	}
	.toc a:visited {
		border-color: #054572;
	}
	.toc a:not(:focus):not(:hover) {
		/* Allow colors to cascade through from link styling */
		border-bottom-color: transparent;
	}

	.toc, .toc ol, .toc ul, .toc li {
		list-style: none; /* Numbers must be inlined into source */
		/* because generated content isn't search/selectable and markers can't do multilevel yet */
		margin:  0;
		padding: 0;
		line-height: 1.1rem; /* consistent spacing */
	}

	/* ToC not indented until third level, but font style & margins show hierarchy */
	.toc > li             { font-weight: bold;   }
	.toc > li li          { font-weight: normal; }
	.toc > li li li       { font-size:   95%;    }
	.toc > li li li li    { font-size:   90%;    }
	.toc > li li li li .secno { font-size: 85%; }
	.toc > li li li li li { font-size:   85%;    }
	.toc > li li li li li .secno { font-size: 100%; }

	/* @supports not (display:grid) { */
		.toc > li             { margin: 1.5rem 0;    }
		.toc > li li          { margin: 0.3rem 0;    }
		.toc > li li li       { margin-left: 2rem;   }

		/* Section numbers in a column of their own */
		.toc .secno {
			float: left;
			width: 4rem;
			white-space: nowrap;
		}

		.toc li {
			clear: both;
		}

		:not(li) > .toc              { margin-left:  5rem; }
		.toc .secno                  { margin-left: -5rem; }
		.toc > li li li .secno       { margin-left: -7rem; }
		.toc > li li li li .secno    { margin-left: -9rem; }
		.toc > li li li li li .secno { margin-left: -11rem; }

		/* Tighten up indentation in narrow ToCs */
		@media (max-width: 30em) {
			:not(li) > .toc              { margin-left:  4rem; }
			.toc .secno                  { margin-left: -4rem; }
			.toc > li li li              { margin-left:  1rem; }
			.toc > li li li .secno       { margin-left: -5rem; }
			.toc > li li li li .secno    { margin-left: -6rem; }
			.toc > li li li li li .secno { margin-left: -7rem; }
		}
	/* } */

	@supports (display:grid) and (display:contents) {
		/* Use #toc over .toc to override non-@supports rules. */
		#toc {
			display: grid;
			align-content: start;
			grid-template-columns: auto 1fr;
			grid-column-gap: 1rem;
			column-gap: 1rem;
			grid-row-gap: .6rem;
			row-gap: .6rem;
		}
		#toc h2 {
			grid-column: 1 / -1;
			margin-bottom: 0;
		}
		#toc ol,
		#toc li,
		#toc a {
			display: contents;
			/* Switch <a> to subgrid when supported */
		}
		#toc span {
			margin: 0;
		}
		#toc > .toc > li > a > span {
			/* The spans of the top-level list,
			   comprising the first items of each top-level section. */
			margin-top: 1.1rem;
		}
		#toc#toc .secno { /* Ugh, need more specificity to override base.css */
			grid-column: 1;
			width: auto;
			margin-left: 0;
		}
		#toc .content {
			grid-column: 2;
			width: auto;
			margin-right: 1rem;
		}
		#toc .content:hover {
			background: rgba(75%, 75%, 75%, .25);
			border-bottom: 3px solid #054572;
			margin-bottom: -3px;
		}
		#toc li li li .content {
			margin-left: 1rem;
		}
		#toc li li li li .content {
			margin-left: 2rem;
		}
	}


/** Index *********************************************************************/

	/* Index Lists: Layout */
	ul.index       { margin-left: 0; columns: 15em; text-indent: 1em hanging; }
	ul.index li    { margin-left: 0; list-style: none; break-inside: avoid; }
	ul.index li li { margin-left: 1em }
	ul.index dl    { margin-top: 0; }
	ul.index dt    { margin: .2em 0 .2em 20px;}
	ul.index dd    { margin: .2em 0 .2em 40px;}
	/* Index Lists: Typography */
	ul.index ul,
	ul.index dl { font-size: smaller; }
	@media not print {
		ul.index li span {
			white-space: nowrap;
			color: transparent; }
		ul.index li a:hover + span,
		ul.index li a:focus + span {
			color: #707070;
		}
	}

/** Index Tables *****************************************************/
	/* See also the data table styling section, which this effectively subclasses */

	table.index {
		font-size: small;
		border-collapse: collapse;
		border-spacing: 0;
		text-align: left;
		margin: 1em 0;
	}

	table.index td,
	table.index th {
		padding: 0.4em;
	}

	table.index tr:hover td:not([rowspan]),
	table.index tr:hover th:not([rowspan]) {
		background: #f7f8f9;
	}

	/* The link in the first column in the property table (formerly a TD) */
	table.index th:first-child a {
		font-weight: bold;
	}

/******************************************************************************/
/*                                    Print                                   */
/******************************************************************************/

	@media print {
		/* Pages have their own margins. */
		html {
			margin: 0;
		}
		/* Serif for print. */
		body {
			font-family: serif;
		}
	}
	@page {
		margin: 1.5cm 1.1cm;
	}

/******************************************************************************/
/*                                    Legacy                                  */
/******************************************************************************/

	/* This rule is inherited from past style sheets. No idea what it's for. */
	.hide { display: none }



/******************************************************************************/
/*                             Overflow Control                               */
/******************************************************************************/

	.figure .caption, .sidefigure .caption, figcaption {
		/* in case figure is overlarge, limit caption to 50em */
		max-width: 50rem;
		margin-left: auto;
		margin-right: auto;
	}
	.overlarge {
		/* Magic to create good table positioning:
		   "content column" is 50ems wide at max; less on smaller screens.
		   Extra space (after ToC + content) is empty on the right.

		   1. When table < content column, centers table in column.
		   2. When content < table < available, left-aligns.
		   3. When table > available, fills available + scroll bar.
		*/ 
		display: grid;
		grid-template-columns: minmax(0, 50em);
	}
	.overlarge > table {
		/* limit preferred width of table */
		max-width: 50em;
		margin-left: auto;
		margin-right: auto;
	}

	@media (min-width: 55em) {
		.overlarge {
			margin-right: calc(13px + 26.5rem - 50vw);
			max-width: none;
		}
	}
	@media screen and (min-width: 78em) {
		body:not(.toc-inline) .overlarge {
			/* 30.5em body padding 50em content area */
			margin-right: calc(40em - 50vw) !important;
		}
	}
	@media screen and (min-width: 90em) {
		body:not(.toc-inline) .overlarge {
			/* 4em html margin 30.5em body padding 50em content area */
			margin-right: calc(84.5em - 100vw) !important;
		}
	}

	@media not print {
		.overlarge {
			overflow-x: auto;
			/* See Lea Verou's explanation background-attachment:
			 * http://lea.verou.me/2012/04/background-attachment-local/
			 *
			background: top left  / 4em 100% linear-gradient(to right,  #ffffff, rgba(255, 255, 255, 0)) local,
			            top right / 4em 100% linear-gradient(to left, #ffffff, rgba(255, 255, 255, 0)) local,
			            top left  / 1em 100% linear-gradient(to right,  #c3c3c5, rgba(195, 195, 197, 0)) scroll,
			            top right / 1em 100% linear-gradient(to left, #c3c3c5, rgba(195, 195, 197, 0)) scroll,
			            white;
			background-repeat: no-repeat;
			*/
		}
	}
</style>
  <link href="https://www.w3.org/StyleSheets/TR/2016/W3C-DREAM" rel="stylesheet" type="text/css">
  <link href="favicon-32x32.png" rel="icon" sizes="32x32" type="image/png">
  <link href="favicon-96x96.png" rel="icon" sizes="96x96" type="image/png">
<style>
  .unstable::before {
    content: "This section is not stable";
    display: block;
    font-weight: bold;
    text-align: right;
    color: red;
  }
  .unstable {
    border: thin solid pink;
    border-radius: .5em;
    padding: .5em;
    margin: .5em calc(-0.5em - 1px);
    background-image: url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' width='300' height='290'><text transform='rotate(-45)' text-anchor='middle' font-family='sans-serif' font-weight='bold' font-size='70' y='210' opacity='.1'>Unstable</text></svg>");
    background-repeat: repeat;
    background-color: #FFF4F4;
  }
  .unstable h3:first-of-type {
    margin-top: 0.5rem;
  }

  .unstable.example:not(.no-marker)::before {
    content: "Example " counter(example) " (Unstable)";
    float: none;
  }

  .non-normative::before {
    content: "This section is non-normative.";
    font-style: italic;
  }
  .tg {
    border-collapse: collapse;
    border-spacing: 0;
  }
  .tg th {
    border-style: solid;
    border-width: 1px;
    background: #90b8de;
    color: #fff;
    font-family: sans-serif;
    font-weight: bold;
    border-color: grey;
  }
  .tg td {
    padding: 4px 5px;
    background-color: rgb(221, 238, 255);
    font-family: monospace;
    border-style: solid;
    border-width: 1px;
    border-color: grey;
    overflow: hidden;
    word-break: normal;
  }
</style>
<style>/* style-md-lists */

/* This is a weird hack for me not yet following the commonmark spec
   regarding paragraph and lists. */
[data-md] > :first-child {
    margin-top: 0;
}
[data-md] > :last-child {
    margin-bottom: 0;
}</style>
<style>/* style-selflinks */

.heading, .issue, .note, .example, li, dt {
    position: relative;
}
a.self-link {
    position: absolute;
    top: 0;
    left: calc(-1 * (3.5rem - 26px));
    width: calc(3.5rem - 26px);
    height: 2em;
    text-align: center;
    border: none;
    transition: opacity .2s;
    opacity: .5;
}
a.self-link:hover {
    opacity: 1;
}
.heading > a.self-link {
    font-size: 83%;
}
li > a.self-link {
    left: calc(-1 * (3.5rem - 26px) - 2em);
}
dfn > a.self-link {
    top: auto;
    left: auto;
    opacity: 0;
    width: 1.5em;
    height: 1.5em;
    background: gray;
    color: white;
    font-style: normal;
    transition: opacity .2s, background-color .2s, color .2s;
}
dfn:hover > a.self-link {
    opacity: 1;
}
dfn > a.self-link:hover {
    color: black;
}

a.self-link::before            { content: "¶"; }
.heading > a.self-link::before { content: "§"; }
dfn > a.self-link::before      { content: "#"; }</style>
<style>/* style-counters */

body {
    counter-reset: example figure issue;
}
.issue {
    counter-increment: issue;
}
.issue:not(.no-marker)::before {
    content: "Issue " counter(issue);
}

.example {
    counter-increment: example;
}
.example:not(.no-marker)::before {
    content: "Example " counter(example);
}
.invalid.example:not(.no-marker)::before,
.illegal.example:not(.no-marker)::before {
    content: "Invalid Example" counter(example);
}

figcaption {
    counter-increment: figure;
}
figcaption:not(.no-marker)::before {
    content: "Figure " counter(figure) " ";
}</style>
<style>/* style-autolinks */

.css.css, .property.property, .descriptor.descriptor {
    color: #005a9c;
    font-size: inherit;
    font-family: inherit;
}
.css::before, .property::before, .descriptor::before {
    content: "‘";
}
.css::after, .property::after, .descriptor::after {
    content: "’";
}
.property, .descriptor {
    /* Don't wrap property and descriptor names */
    white-space: nowrap;
}
.type { /* CSS value <type> */
    font-style: italic;
}
pre .property::before, pre .property::after {
    content: "";
}
[data-link-type="property"]::before,
[data-link-type="propdesc"]::before,
[data-link-type="descriptor"]::before,
[data-link-type="value"]::before,
[data-link-type="function"]::before,
[data-link-type="at-rule"]::before,
[data-link-type="selector"]::before,
[data-link-type="maybe"]::before {
    content: "‘";
}
[data-link-type="property"]::after,
[data-link-type="propdesc"]::after,
[data-link-type="descriptor"]::after,
[data-link-type="value"]::after,
[data-link-type="function"]::after,
[data-link-type="at-rule"]::after,
[data-link-type="selector"]::after,
[data-link-type="maybe"]::after {
    content: "’";
}

[data-link-type].production::before,
[data-link-type].production::after,
.prod [data-link-type]::before,
.prod [data-link-type]::after {
    content: "";
}

[data-link-type=element],
[data-link-type=element-attr] {
    font-family: Menlo, Consolas, "DejaVu Sans Mono", monospace;
    font-size: .9em;
}
[data-link-type=element]::before { content: "<" }
[data-link-type=element]::after  { content: ">" }

[data-link-type=biblio] {
    white-space: pre;
}</style>
<style>/* style-dfn-panel */

.dfn-panel {
    position: absolute;
    z-index: 35;
    height: auto;
    width: -webkit-fit-content;
    width: fit-content;
    max-width: 300px;
    max-height: 500px;
    overflow: auto;
    padding: 0.5em 0.75em;
    font: small Helvetica Neue, sans-serif, Droid Sans Fallback;
    background: #DDDDDD;
    color: black;
    border: outset 0.2em;
}
.dfn-panel:not(.on) { display: none; }
.dfn-panel * { margin: 0; padding: 0; text-indent: 0; }
.dfn-panel > b { display: block; }
.dfn-panel a { color: black; }
.dfn-panel a:not(:hover) { text-decoration: none !important; border-bottom: none !important; }
.dfn-panel > b + b { margin-top: 0.25em; }
.dfn-panel ul { padding: 0; }
.dfn-panel li { list-style: inside; }
.dfn-panel.activated {
    display: inline-block;
    position: fixed;
    left: .5em;
    bottom: 2em;
    margin: 0 auto;
    max-width: calc(100vw - 1.5em - .4em - .5em);
    max-height: 30vh;
}

.dfn-paneled { cursor: pointer; }
</style>
<style>/* style-syntax-highlighting */
pre.idl.highlight { color: #708090; }
.highlight:not(.idl) { background: hsl(24, 20%, 95%); }
code.highlight { padding: .1em; border-radius: .3em; }
pre.highlight, pre > code.highlight { display: block; padding: 1em; margin: .5em 0; overflow: auto; border-radius: 0; }
c-[a] { color: #990055 } /* Keyword.Declaration */
c-[b] { color: #990055 } /* Keyword.Type */
c-[c] { color: #708090 } /* Comment */
c-[d] { color: #708090 } /* Comment.Multiline */
c-[e] { color: #0077aa } /* Name.Attribute */
c-[f] { color: #669900 } /* Name.Tag */
c-[g] { color: #222222 } /* Name.Variable */
c-[k] { color: #990055 } /* Keyword */
c-[l] { color: #000000 } /* Literal */
c-[m] { color: #000000 } /* Literal.Number */
c-[n] { color: #0077aa } /* Name */
c-[o] { color: #999999 } /* Operator */
c-[p] { color: #999999 } /* Punctuation */
c-[s] { color: #a67f59 } /* Literal.String */
c-[t] { color: #a67f59 } /* Literal.String.Single */
c-[u] { color: #a67f59 } /* Literal.String.Double */
c-[cp] { color: #708090 } /* Comment.Preproc */
c-[c1] { color: #708090 } /* Comment.Single */
c-[cs] { color: #708090 } /* Comment.Special */
c-[kc] { color: #990055 } /* Keyword.Constant */
c-[kn] { color: #990055 } /* Keyword.Namespace */
c-[kp] { color: #990055 } /* Keyword.Pseudo */
c-[kr] { color: #990055 } /* Keyword.Reserved */
c-[ld] { color: #000000 } /* Literal.Date */
c-[nc] { color: #0077aa } /* Name.Class */
c-[no] { color: #0077aa } /* Name.Constant */
c-[nd] { color: #0077aa } /* Name.Decorator */
c-[ni] { color: #0077aa } /* Name.Entity */
c-[ne] { color: #0077aa } /* Name.Exception */
c-[nf] { color: #0077aa } /* Name.Function */
c-[nl] { color: #0077aa } /* Name.Label */
c-[nn] { color: #0077aa } /* Name.Namespace */
c-[py] { color: #0077aa } /* Name.Property */
c-[ow] { color: #999999 } /* Operator.Word */
c-[mb] { color: #000000 } /* Literal.Number.Bin */
c-[mf] { color: #000000 } /* Literal.Number.Float */
c-[mh] { color: #000000 } /* Literal.Number.Hex */
c-[mi] { color: #000000 } /* Literal.Number.Integer */
c-[mo] { color: #000000 } /* Literal.Number.Oct */
c-[sb] { color: #a67f59 } /* Literal.String.Backtick */
c-[sc] { color: #a67f59 } /* Literal.String.Char */
c-[sd] { color: #a67f59 } /* Literal.String.Doc */
c-[se] { color: #a67f59 } /* Literal.String.Escape */
c-[sh] { color: #a67f59 } /* Literal.String.Heredoc */
c-[si] { color: #a67f59 } /* Literal.String.Interpol */
c-[sx] { color: #a67f59 } /* Literal.String.Other */
c-[sr] { color: #a67f59 } /* Literal.String.Regex */
c-[ss] { color: #a67f59 } /* Literal.String.Symbol */
c-[vc] { color: #0077aa } /* Name.Variable.Class */
c-[vg] { color: #0077aa } /* Name.Variable.Global */
c-[vi] { color: #0077aa } /* Name.Variable.Instance */
c-[il] { color: #000000 } /* Literal.Number.Integer.Long */
</style>
 <body class="h-entry">
  <div class="head">
   <p data-fill-with="logo"><a class="logo" href="https://www.w3.org/"> <img alt="W3C" height="48" src="https://www.w3.org/StyleSheets/TR/2016/logos/W3C" width="72"> </a> </p>
   <h1 class="p-name no-ref" id="title">WebXR Meshing API Level 1</h1>
   <h2 class="no-num no-toc no-ref heading settled" id="subtitle"><span class="content">A Collection of Interesting Ideas, <time class="dt-updated" datetime="1970-01-01">1 January 1970</time></span></h2>
   <div data-fill-with="spec-metadata">
    <dl>
     <dt>Previous Versions:
     <dd><a href rel="prev"></a>
     <dt class="editor">Editors:
     <dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:rcabanier@magicleap.com">Rik Cabanier</a> (<a class="p-org org" href="https://magicleap.com">Magic Leap</a>)
     <dd class="editor p-author h-card vcard"><span class="p-name fn"></span>
    </dl>
   </div>
   <div data-fill-with="warning"></div>
   <p class="copyright" data-fill-with="copyright"><a href="https://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 1970 <a href="https://www.w3.org/"><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a href="https://www.csail.mit.edu/"><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>, <a href="https://www.ercim.eu/"><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>, <a href="https://www.keio.ac.jp/">Keio</a>, <a href="https://ev.buaa.edu.cn/">Beihang</a>). W3C <a href="https://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="https://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href="https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document" rel="license">permissive document license</a> rules apply. </p>
   <hr title="Separator for header">
  </div>
  <div class="p-summary" data-fill-with="abstract">
   <h2 class="no-num no-toc no-ref heading settled" id="abstract"><span class="content">Abstract</span></h2>
   <p>This specification describes support for accessing the geometry of real world objects during a WebXR session.</p>
  </div>
  <h2 class="no-num no-toc no-ref heading settled" id="status"><span class="content">Status of this document</span></h2>
  <div data-fill-with="status">
   <p></p>
  </div>
  <div data-fill-with="at-risk"></div>
  <nav data-fill-with="table-of-contents" id="toc">
   <h2 class="no-num no-toc no-ref" id="contents">Table of Contents</h2>
   <ol class="toc" role="directory">
    <li>
     <a href="#intro"><span class="secno">1</span> <span class="content">Introduction</span></a>
     <ol class="toc">
      <li><a href="#terminology"><span class="secno">1.1</span> <span class="content">Terminology</span></a>
      <li><a href="#applicationflow"><span class="secno">1.2</span> <span class="content">Application flow</span></a>
     </ol>
    <li>
     <a href="#initialization"><span class="secno">2</span> <span class="content">Initialization</span></a>
     <ol class="toc">
      <li><a href="#xr--mesh-quality"><span class="secno">2.1</span> <span class="content">XRMeshQuality</span></a>
      <li><a href="#xr-world-mesh-feature"><span class="secno">2.2</span> <span class="content">XRWorldMeshFeature</span></a>
      <li><a href="#xr-near-mesh-feature"><span class="secno">2.3</span> <span class="content">XRNearMeshFeature</span></a>
     </ol>
    <li>
     <a href="#frame"><span class="secno">3</span> <span class="content">Frame Loop</span></a>
     <ol class="toc">
      <li><a href="#xrframe-structures"><span class="secno">3.1</span> <span class="content">XRMesh structures</span></a>
      <li><a href="#xrframe-interface"><span class="secno">3.2</span> <span class="content">XRFrame</span></a>
     </ol>
    <li><a href="#security"><span class="secno">4</span> <span class="content">Security and Privacy Considerations</span></a>
    <li>
     <a href="#index"><span class="secno"></span> <span class="content">Index</span></a>
     <ol class="toc">
      <li><a href="#index-defined-here"><span class="secno"></span> <span class="content">Terms defined by this specification</span></a>
      <li><a href="#index-defined-elsewhere"><span class="secno"></span> <span class="content">Terms defined by reference</span></a>
     </ol>
    <li>
     <a href="#references"><span class="secno"></span> <span class="content">References</span></a>
     <ol class="toc">
      <li><a href="#normative"><span class="secno"></span> <span class="content">Normative References</span></a>
     </ol>
    <li><a href="#idl-index"><span class="secno"></span> <span class="content">IDL Index</span></a>
    <li><a href="#issues-index"><span class="secno"></span> <span class="content">Issues Index</span></a>
   </ol>
  </nav>
  <main>
   <h2 class="heading settled" data-level="1" id="intro"><span class="secno">1. </span><span class="content">Introduction</span><a class="self-link" href="#intro"></a></h2>
   <section class="non-normative">
    <p>Meshing is a technique that uses a device’s sensors to build a 3 dimensional representation of the world.</p>
    <p>The mesh consists of a large collection of geometry of medium complexity that changes slowly over time (aka the world mesh) and a very small collection of complex quickly changing content that represents the geometry close to the user (aka the near mesh).</p>
    <p>A user agent can have support for no, one or both types of geometry and the website author can request one or both types of geometry data. Requesting the geometry data is an expensive process so an author should only request it if they will do something with the information.</p>
    <p>Typically mesh data is not used to determine things like hand gestures or the recognition of real world objects. (However a UA could choose to infer this through postprocessing.)</p>
    <p>The most common use cases for the world mesh are:</p>
    <ol>
     <li data-md>
      <p>physics: interaction of virtual objects with the real world</p>
     <li data-md>
      <p>occlusion: blocking part or the whole virtual object by a real world one</p>
    </ol>
    <p>The most common use cases for the near mesh are:</p>
    <ol>
     <li data-md>
      <p>a visual representation of objects near the viewer.</p>
     <li data-md>
      <p>occlusion</p>
    </ol>
   </section>
   <h3 class="heading settled" data-level="1.1" id="terminology"><span class="secno">1.1. </span><span class="content">Terminology</span><a class="self-link" href="#terminology"></a></h3>
   <h3 class="heading settled" data-level="1.2" id="applicationflow"><span class="secno">1.2. </span><span class="content">Application flow</span><a class="self-link" href="#applicationflow"></a></h3>
   <section class="non-normative">
    <p>Most applications using the WebXR Meshing API will follow a similar usage pattern:</p>
    <ul>
     <li data-md>
      <p>During the creation of a WebXR session, pass a XRFeatureInit object with parameters for world and near mesh.</p>
     <li data-md>
      <p>For each XRFrame, get the requested mesh data and apply it to the scene.</p>
    </ul>
   </section>
   <h2 class="heading settled" data-level="2" id="initialization"><span class="secno">2. </span><span class="content">Initialization</span><a class="self-link" href="#initialization"></a></h2>
   <h3 class="heading settled" data-level="2.1" id="xr--mesh-quality"><span class="secno">2.1. </span><span class="content">XRMeshQuality</span><a class="self-link" href="#xr--mesh-quality"></a></h3>
<pre class="idl highlight def"><c- b>enum</c-> <dfn class="dfn-paneled idl-code" data-dfn-type="enum" data-export id="enumdef-xrmeshquality"><code><c- g>XRMeshQuality</c-></code></dfn> {
   <dfn class="idl-code" data-dfn-for="XRMeshQuality" data-dfn-type="enum-value" data-export id="dom-xrmeshquality-low"><code><c- s>"low"</c-></code><a class="self-link" href="#dom-xrmeshquality-low"></a></dfn>,
   <dfn class="idl-code" data-dfn-for="XRMeshQuality" data-dfn-type="enum-value" data-export id="dom-xrmeshquality-medium"><code><c- s>"medium"</c-></code><a class="self-link" href="#dom-xrmeshquality-medium"></a></dfn>,
   <dfn class="idl-code" data-dfn-for="XRMeshQuality" data-dfn-type="enum-value" data-export id="dom-xrmeshquality-high"><code><c- s>"high"</c-></code><a class="self-link" href="#dom-xrmeshquality-high"></a></dfn>
};
</pre>
   <p><code class="idl"><a data-link-type="idl" href="#enumdef-xrmeshquality" id="ref-for-enumdef-xrmeshquality">XRMeshQuality</a></code> defines the quality of the mesh. A higher quality means that the mesh will be finer but also more resource intensive. It is up to the UA to define the quality level.</p>
   <h3 class="heading settled" data-level="2.2" id="xr-world-mesh-feature"><span class="secno">2.2. </span><span class="content">XRWorldMeshFeature</span><a class="self-link" href="#xr-world-mesh-feature"></a></h3>
   <p>The "worldmesh" feature is used to request world meshing.</p>
<pre class="idl highlight def"><c- b>dictionary</c-> <dfn class="idl-code" data-dfn-type="dictionary" data-export id="dictdef-xrworldmeshfeature"><code><c- g>XRWorldMeshFeature</c-></code><a class="self-link" href="#dictdef-xrworldmeshfeature"></a></dfn>: <a class="n" data-link-type="idl-name"><c- n>XRFeatureInit</c-></a> {
    <a class="n" data-link-type="idl-name" href="#enumdef-xrmeshquality" id="ref-for-enumdef-xrmeshquality①"><c- n>XRMeshQuality</c-></a> <dfn class="idl-code" data-default="&quot;medium&quot;" data-dfn-for="XRWorldMeshFeature" data-dfn-type="dict-member" data-export data-type="XRMeshQuality " id="dom-xrworldmeshfeature-quality"><code><c- g>quality</c-></code><a class="self-link" href="#dom-xrworldmeshfeature-quality"></a></dfn> = "medium";
    <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-double" id="ref-for-idl-double"><c- b>double</c-></a> <dfn class="idl-code" data-default="10.0" data-dfn-for="XRWorldMeshFeature" data-dfn-type="dict-member" data-export data-type="double " id="dom-xrworldmeshfeature-width"><code><c- g>width</c-></code><a class="self-link" href="#dom-xrworldmeshfeature-width"></a></dfn> = 10.0;
    <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-double" id="ref-for-idl-double①"><c- b>double</c-></a> <dfn class="idl-code" data-default="10.0" data-dfn-for="XRWorldMeshFeature" data-dfn-type="dict-member" data-export data-type="double " id="dom-xrworldmeshfeature-height"><code><c- g>height</c-></code><a class="self-link" href="#dom-xrworldmeshfeature-height"></a></dfn> = 10.0;
    <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-double" id="ref-for-idl-double②"><c- b>double</c-></a> <dfn class="idl-code" data-default="10.0" data-dfn-for="XRWorldMeshFeature" data-dfn-type="dict-member" data-export data-type="double " id="dom-xrworldmeshfeature-breadth"><code><c- g>breadth</c-></code><a class="self-link" href="#dom-xrworldmeshfeature-breadth"></a></dfn> = 10.0;
};
</pre>
   <p>The <dfn class="idl-code" data-dfn-for="XRWorldMeshFeature/width" data-dfn-type="attribute" data-export id="dom-xrworldmeshfeature-width-width"><code>width</code><a class="self-link" href="#dom-xrworldmeshfeature-width-width"></a></dfn>, <dfn class="idl-code" data-dfn-for="XRWorldMeshFeature/height" data-dfn-type="attribute" data-export id="dom-xrworldmeshfeature-height-height"><code>height</code><a class="self-link" href="#dom-xrworldmeshfeature-height-height"></a></dfn> and <dfn class="idl-code" data-dfn-for="XRWorldMeshFeature/breadth" data-dfn-type="attribute" data-export id="dom-xrworldmeshfeature-breadth-breadth"><code>breadth</code><a class="self-link" href="#dom-xrworldmeshfeature-breadth-breadth"></a></dfn> attributes define the distance, in meters, of the width, height and breadth of the area around the observer that should be meshed.
The <dfn class="idl-code" data-dfn-for="XRWorldMeshFeature/quality" data-dfn-type="attribute" data-export id="dom-xrworldmeshfeature-quality-quality"><code>quality</code><a class="self-link" href="#dom-xrworldmeshfeature-quality-quality"></a></dfn> attribute defines the UA dependent quality of the mesh.</p>
   <div class="example" id="example-c88961b1">
    <a class="self-link" href="#example-c88961b1"></a> The following code attempts to create an <code class="idl"><a data-link-type="idl">immersive-ar</a></code> <code class="idl"><a data-link-type="idl">XRSession</a></code> with world meshing. 
<pre class="highlight"><c- a>let</c-> xrSession<c- p>;</c->

navigator<c- p>.</c->xr<c- p>.</c->requestSession<c- p>(</c-><c- u>"immersive-ar"</c-><c- p>,</c-> <c- p>{</c->
                            requiredFeature<c- o>:</c-> <c- p>{</c->
                                name<c- o>:</c-> <c- u>"XRWorldMeshFeature"</c-><c- p>,</c->
                                quality<c- o>:</c-> <c- u>"medium"</c-><c- p>}}).</c->then<c- p>((</c->session<c- p>)</c-> <c- p>=></c-> <c- p>{</c->
    xrSession <c- o>=</c-> session<c- p>;</c->
<c- p>});</c->
</pre>
   </div>
   <p class="issue" id="issue-d4b98141"><a class="self-link" href="#issue-d4b98141"></a> should the world mesh follow the observer or should it stay relative to the original position or should it be configurable?</p>
   <p class="issue" id="issue-15434211"><a class="self-link" href="#issue-15434211"></a> should the world mesh have an XRSpace?</p>
   <h3 class="heading settled" data-level="2.3" id="xr-near-mesh-feature"><span class="secno">2.3. </span><span class="content">XRNearMeshFeature</span><a class="self-link" href="#xr-near-mesh-feature"></a></h3>
   <p>The "nearmesh" feature is used to request meshing near the observer. It is UA dependent what the scanned area for the near mesh is but it MUST not overlap with the world mesh.</p>
<pre class="idl highlight def"><c- b>dictionary</c-> <dfn class="idl-code" data-dfn-type="dictionary" data-export id="dictdef-xrnearmeshfeature"><code><c- g>XRNearMeshFeature</c-></code><a class="self-link" href="#dictdef-xrnearmeshfeature"></a></dfn>: <a class="n" data-link-type="idl-name"><c- n>XRFeatureInit</c-></a> {
    <a class="n" data-link-type="idl-name" href="#enumdef-xrmeshquality" id="ref-for-enumdef-xrmeshquality②"><c- n>XRMeshQuality</c-></a> <dfn class="idl-code" data-default="&quot;medium&quot;" data-dfn-for="XRNearMeshFeature" data-dfn-type="dict-member" data-export data-type="XRMeshQuality " id="dom-xrnearmeshfeature-quality"><code><c- g>quality</c-></code><a class="self-link" href="#dom-xrnearmeshfeature-quality"></a></dfn> = "medium";
};
</pre>
   <p>The <dfn class="idl-code" data-dfn-for="XRNearMeshFeature/quality" data-dfn-type="attribute" data-export id="dom-xrnearmeshfeature-quality-quality"><code>quality</code><a class="self-link" href="#dom-xrnearmeshfeature-quality-quality"></a></dfn> attribute defines the UA dependent quality of the mesh.</p>
   <div class="example" id="example-79734e31">
    <a class="self-link" href="#example-79734e31"></a> The following code attempts to create an <code class="idl"><a data-link-type="idl">immersive-ar</a></code> <code class="idl"><a data-link-type="idl">XRSession</a></code> with near meshing. 
<pre class="highlight"><c- a>let</c-> xrSession<c- p>;</c->

navigator<c- p>.</c->xr<c- p>.</c->requestSession<c- p>(</c-><c- u>"immersive-vr"</c-><c- p>,</c-> <c- p>{</c->
                            requiredFeature<c- o>:</c-> <c- p>{</c->
                                name<c- o>:</c-> <c- u>"XRNearMeshFeature"</c-><c- p>,</c->
                                quality<c- o>:</c-> <c- u>"low"</c-><c- p>}}).</c->then<c- p>((</c->session<c- p>)</c-> <c- p>=></c-> <c- p>{</c->
    xrSession <c- o>=</c-> session<c- p>;</c->
<c- p>});</c->
</pre>
   </div>
   <p class="issue" id="issue-a32157e9"><a class="self-link" href="#issue-a32157e9"></a> should the near mesh have an XRSpace?</p>
   <h2 class="heading settled" data-level="3" id="frame"><span class="secno">3. </span><span class="content">Frame Loop</span><a class="self-link" href="#frame"></a></h2>
   <h3 class="heading settled" data-level="3.1" id="xrframe-structures"><span class="secno">3.1. </span><span class="content">XRMesh structures</span><a class="self-link" href="#xrframe-structures"></a></h3>
<pre class="idl highlight def"><c- b>dictionary</c-> <dfn class="dfn-paneled idl-code" data-dfn-type="dictionary" data-export id="dictdef-xrmeshblock"><code><c- g>XRMeshBlock</c-></code></dfn> {
    <c- b>required</c-> <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-Float32Array" id="ref-for-idl-Float32Array"><c- b>Float32Array</c-></a> <dfn class="dfn-paneled idl-code" data-dfn-for="XRMeshBlock" data-dfn-type="dict-member" data-export data-type="Float32Array " id="dom-xrmeshblock-vertices"><code><c- g>vertices</c-></code></dfn>;
    <c- b>required</c-> <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-Uint16Array" id="ref-for-idl-Uint16Array"><c- b>Uint16Array</c-></a> <dfn class="dfn-paneled idl-code" data-dfn-for="XRMeshBlock" data-dfn-type="dict-member" data-export data-type="Uint16Array " id="dom-xrmeshblock-indices"><code><c- g>indices</c-></code></dfn>;
    <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-Float32Array" id="ref-for-idl-Float32Array①"><c- b>Float32Array</c-></a> <dfn class="dfn-paneled idl-code" data-dfn-for="XRMeshBlock" data-dfn-type="dict-member" data-export data-type="Float32Array " id="dom-xrmeshblock-normals"><code><c- g>normals</c-></code></dfn>;
};
</pre>
   <p>A <code class="idl"><a data-link-type="idl" href="#dictdef-xrmeshblock" id="ref-for-dictdef-xrmeshblock">XRMeshBlock</a></code> contains the geometry data of a single mesh instance.</p>
   <p><code class="idl"><a data-link-type="idl" href="#dom-xrmeshblock-vertices" id="ref-for-dom-xrmeshblock-vertices">vertices</a></code> contains a buffer with points in 3D space. Each point consists of 3 floats.</p>
   <p>Each value in <code class="idl"><a data-link-type="idl" href="#dom-xrmeshblock-indices" id="ref-for-dom-xrmeshblock-indices">indices</a></code> points to an offset into a point inside <code class="idl"><a data-link-type="idl" href="#dom-xrmeshblock-vertices" id="ref-for-dom-xrmeshblock-vertices①">vertices</a></code> and defines the corner of a triangle. The set of triangles creates a polygon mesh.
NOTE: the offset of each point is found by taking the index value and multiplying by 3.</p>
   <p><code class="idl"><a data-link-type="idl" href="#dictdef-xrmeshblock" id="ref-for-dictdef-xrmeshblock①">XRMeshBlock</a></code> can contain an optional <code class="idl"><a data-link-type="idl" href="#dom-xrmeshblock-normals" id="ref-for-dom-xrmeshblock-normals">normals</a></code> which defines a buffer with the normal of each vertex. The size of <code class="idl"><a data-link-type="idl" href="#dom-xrmeshblock-normals" id="ref-for-dom-xrmeshblock-normals①">normals</a></code> must be the same as <code class="idl"><a data-link-type="idl" href="#dom-xrmeshblock-vertices" id="ref-for-dom-xrmeshblock-vertices②">vertices</a></code>.</p>
   <p class="issue" id="issue-27e155ec"><a class="self-link" href="#issue-27e155ec"></a> is <a class="property" data-link-type="propdesc">normals</a> needed? If so, should it be requested during initialisation?</p>
<pre class="idl highlight def"><c- b>interface</c-> <dfn class="dfn-paneled idl-code" data-dfn-type="interface" data-export id="xrnearmesh"><code><c- g>XRNearMesh</c-></code></dfn> {
    <c- b>readonly</c-> <c- b>setlike</c->&lt;<a class="n" data-link-type="idl-name" href="#dictdef-xrmeshblock" id="ref-for-dictdef-xrmeshblock②"><c- n>XRMeshBlock</c-></a>>;
};

<c- b>interface</c-> <dfn class="dfn-paneled idl-code" data-dfn-type="interface" data-export id="xrworldmesh"><code><c- g>XRWorldMesh</c-></code></dfn> {
    <c- b>readonly</c-> <c- b>maplike</c->&lt;<a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-DOMString" id="ref-for-idl-DOMString"><c- b>DOMString</c-></a>, <a class="n" data-link-type="idl-name" href="#dictdef-xrmeshblock" id="ref-for-dictdef-xrmeshblock③"><c- n>XRMeshBlock</c-></a>>;
};

<c- b>dictionary</c-> <dfn class="dfn-paneled idl-code" data-dfn-type="dictionary" data-export id="dictdef-xrmetadata"><code><c- g>XRMetadata</c-></code></dfn> {
    <a class="n" data-link-type="idl-name" href="#xrworldmesh" id="ref-for-xrworldmesh"><c- n>XRWorldMesh</c-></a> <a class="idl-code" data-link-type="dict-member" data-type="XRWorldMesh " href="#dom-xrmetadata-worldmesh" id="ref-for-dom-xrmetadata-worldmesh"><c- g>worldMesh</c-></a>;
    <a class="n" data-link-type="idl-name" href="#xrnearmesh" id="ref-for-xrnearmesh"><c- n>XRNearMesh</c-></a> <a class="idl-code" data-link-type="dict-member" data-type="XRNearMesh " href="#dom-xrmetadata-nearmesh" id="ref-for-dom-xrmetadata-nearmesh"><c- g>nearMesh</c-></a>;
};
</pre>
   <p>The <dfn class="dfn-paneled idl-code" data-dfn-for="XRMetadata" data-dfn-type="dict-member" data-export id="dom-xrmetadata-worldmesh"><code>worldMesh</code></dfn> attribute contains updates to the world mesh. If any key in the dictionary was a previously provided provided <a data-link-type="dfn">XRWorldMesh</a> this new value must replace the previous <a data-link-type="dfn">XRMeshBlock</a>. If the value of a new world XRMeshBlock contains no vertices, the existing XRMeshBlock must be deleted.</p>
   <p>The <dfn class="dfn-paneled idl-code" data-dfn-for="XRMetadata" data-dfn-type="dict-member" data-export id="dom-xrmetadata-nearmesh"><code>nearMesh</code></dfn> attribute contains a new near mesh which will replace the previous near mesh (if any). If nearMesh contains no new XRMeshBlock object, there is no near mesh.</p>
   <h3 class="heading settled" data-level="3.2" id="xrframe-interface"><span class="secno">3.2. </span><span class="content">XRFrame</span><a class="self-link" href="#xrframe-interface"></a></h3>
<pre class="idl highlight def"><c- b>partial</c-> <c- b>interface</c-> <a class="idl-code" data-link-type="interface"><c- g>XRFrame</c-></a> {
    <c- b>readonly</c-> <c- b>attribute</c-> <a class="n" data-link-type="idl-name" href="#dictdef-xrmetadata" id="ref-for-dictdef-xrmetadata"><c- n>XRMetadata</c-></a> <dfn class="idl-code" data-dfn-for="XRFrame" data-dfn-type="attribute" data-export data-readonly data-type="XRMetadata" id="dom-xrframe-metadata"><code><c- g>metaData</c-></code><a class="self-link" href="#dom-xrframe-metadata"></a></dfn>;
};
</pre>
   <p>Each XRFrame contains a <dfn class="idl-code" data-dfn-for="XRFrame" data-dfn-type="dict-member" data-export id="dom-xrframe-metadata①"><code>metaData</code><a class="self-link" href="#dom-xrframe-metadata①"></a></dfn> attribute with new or updated world or near mesh data.</p>
   <p class="issue" id="issue-ffb06508"><a class="self-link" href="#issue-ffb06508"></a> should the mesh data persist per browser session or per xr session?</p>
   <h2 class="heading settled" data-level="4" id="security"><span class="secno">4. </span><span class="content">Security and Privacy Considerations</span><a class="self-link" href="#security"></a></h2>
   <p>The WebXR Meshing API is a powerful feature with that carries significant privacy risks.
A UA MUST ask permission from the user during session creation before meshing data is returned to the page.</p>
   <p>An <a class="property" data-link-type="propdesc">inline</a> session must NOT have access to mesh data.</p>
   <p>Additionally, mesh data MUST be constructed from the geometry of the real world. It MUST not reveal writing, colors, pictures or other visual content.</p>
   <p class="issue" id="issue-22eb3e63"><a class="self-link" href="#issue-22eb3e63"></a> clarify this section</p>
   <p id="back-to-top" role="navigation"><a href="#toc"><abbr title="Back to Top">↑</abbr></a></p>
<script src="https://www.w3.org/scripts/TR/2016/fixup.js"></script>
  </main>
  <h2 class="no-num no-ref heading settled" id="index"><span class="content">Index</span><a class="self-link" href="#index"></a></h2>
  <h3 class="no-num no-ref heading settled" id="index-defined-here"><span class="content">Terms defined by this specification</span><a class="self-link" href="#index-defined-here"></a></h3>
  <ul class="index">
   <li>
    breadth
    <ul>
     <li><a href="#dom-xrworldmeshfeature-breadth-breadth">attribute for XRWorldMeshFeature/breadth</a><span>, in §2.2</span>
     <li><a href="#dom-xrworldmeshfeature-breadth">dict-member for XRWorldMeshFeature</a><span>, in §2.2</span>
    </ul>
   <li>
    height
    <ul>
     <li><a href="#dom-xrworldmeshfeature-height-height">attribute for XRWorldMeshFeature/height</a><span>, in §2.2</span>
     <li><a href="#dom-xrworldmeshfeature-height">dict-member for XRWorldMeshFeature</a><span>, in §2.2</span>
    </ul>
   <li><a href="#dom-xrmeshquality-high">"high"</a><span>, in §2.1</span>
   <li><a href="#dom-xrmeshblock-indices">indices</a><span>, in §3.1</span>
   <li><a href="#dom-xrmeshquality-low">"low"</a><span>, in §2.1</span>
   <li><a href="#dom-xrmeshquality-medium">"medium"</a><span>, in §2.1</span>
   <li>
    metaData
    <ul>
     <li><a href="#dom-xrframe-metadata">attribute for XRFrame</a><span>, in §3.2</span>
     <li><a href="#dom-xrframe-metadata①">dict-member for XRFrame</a><span>, in §3.2</span>
    </ul>
   <li><a href="#dom-xrmetadata-nearmesh">nearMesh</a><span>, in §3.1</span>
   <li><a href="#dom-xrmeshblock-normals">normals</a><span>, in §3.1</span>
   <li>
    quality
    <ul>
     <li><a href="#dom-xrnearmeshfeature-quality-quality">attribute for XRNearMeshFeature/quality</a><span>, in §2.3</span>
     <li><a href="#dom-xrworldmeshfeature-quality-quality">attribute for XRWorldMeshFeature/quality</a><span>, in §2.2</span>
     <li><a href="#dom-xrnearmeshfeature-quality">dict-member for XRNearMeshFeature</a><span>, in §2.3</span>
     <li><a href="#dom-xrworldmeshfeature-quality">dict-member for XRWorldMeshFeature</a><span>, in §2.2</span>
    </ul>
   <li><a href="#dom-xrmeshblock-vertices">vertices</a><span>, in §3.1</span>
   <li>
    width
    <ul>
     <li><a href="#dom-xrworldmeshfeature-width-width">attribute for XRWorldMeshFeature/width</a><span>, in §2.2</span>
     <li><a href="#dom-xrworldmeshfeature-width">dict-member for XRWorldMeshFeature</a><span>, in §2.2</span>
    </ul>
   <li><a href="#dom-xrmetadata-worldmesh">worldMesh</a><span>, in §3.1</span>
   <li><a href="#dictdef-xrmeshblock">XRMeshBlock</a><span>, in §3.1</span>
   <li><a href="#enumdef-xrmeshquality">XRMeshQuality</a><span>, in §2.1</span>
   <li><a href="#dictdef-xrmetadata">XRMetadata</a><span>, in §3.1</span>
   <li><a href="#xrnearmesh">XRNearMesh</a><span>, in §3.1</span>
   <li><a href="#dictdef-xrnearmeshfeature">XRNearMeshFeature</a><span>, in §2.3</span>
   <li><a href="#xrworldmesh">XRWorldMesh</a><span>, in §3.1</span>
   <li><a href="#dictdef-xrworldmeshfeature">XRWorldMeshFeature</a><span>, in §2.2</span>
  </ul>
  <aside class="dfn-panel" data-for="term-for-idl-DOMString">
   <a href="https://heycam.github.io/webidl/#idl-DOMString">https://heycam.github.io/webidl/#idl-DOMString</a><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-idl-DOMString">3.1. XRMesh structures</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="term-for-idl-Float32Array">
   <a href="https://heycam.github.io/webidl/#idl-Float32Array">https://heycam.github.io/webidl/#idl-Float32Array</a><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-idl-Float32Array">3.1. XRMesh structures</a> <a href="#ref-for-idl-Float32Array①">(2)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="term-for-idl-Uint16Array">
   <a href="https://heycam.github.io/webidl/#idl-Uint16Array">https://heycam.github.io/webidl/#idl-Uint16Array</a><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-idl-Uint16Array">3.1. XRMesh structures</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="term-for-idl-double">
   <a href="https://heycam.github.io/webidl/#idl-double">https://heycam.github.io/webidl/#idl-double</a><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-idl-double">2.2. XRWorldMeshFeature</a> <a href="#ref-for-idl-double①">(2)</a> <a href="#ref-for-idl-double②">(3)</a>
   </ul>
  </aside>
  <h3 class="no-num no-ref heading settled" id="index-defined-elsewhere"><span class="content">Terms defined by reference</span><a class="self-link" href="#index-defined-elsewhere"></a></h3>
  <ul class="index">
   <li>
    <a data-link-type="biblio">[WebIDL]</a> defines the following terms:
    <ul>
     <li><span class="dfn-paneled" id="term-for-idl-DOMString" style="color:initial">DOMString</span>
     <li><span class="dfn-paneled" id="term-for-idl-Float32Array" style="color:initial">Float32Array</span>
     <li><span class="dfn-paneled" id="term-for-idl-Uint16Array" style="color:initial">Uint16Array</span>
     <li><span class="dfn-paneled" id="term-for-idl-double" style="color:initial">double</span>
    </ul>
  </ul>
  <h2 class="no-num no-ref heading settled" id="references"><span class="content">References</span><a class="self-link" href="#references"></a></h2>
  <h3 class="no-num no-ref heading settled" id="normative"><span class="content">Normative References</span><a class="self-link" href="#normative"></a></h3>
  <dl>
   <dt id="biblio-webidl">[WebIDL]
   <dd>Boris Zbarsky. <a href="https://heycam.github.io/webidl/">Web IDL</a>. 15 December 2016. ED. URL: <a href="https://heycam.github.io/webidl/">https://heycam.github.io/webidl/</a>
  </dl>
  <h2 class="no-num no-ref heading settled" id="idl-index"><span class="content">IDL Index</span><a class="self-link" href="#idl-index"></a></h2>
<pre class="idl highlight def"><c- b>enum</c-> <a href="#enumdef-xrmeshquality"><code><c- g>XRMeshQuality</c-></code></a> {
   <a href="#dom-xrmeshquality-low"><code><c- s>"low"</c-></code></a>,
   <a href="#dom-xrmeshquality-medium"><code><c- s>"medium"</c-></code></a>,
   <a href="#dom-xrmeshquality-high"><code><c- s>"high"</c-></code></a>
};

<c- b>dictionary</c-> <a href="#dictdef-xrworldmeshfeature"><code><c- g>XRWorldMeshFeature</c-></code></a>: <a class="n" data-link-type="idl-name"><c- n>XRFeatureInit</c-></a> {
    <a class="n" data-link-type="idl-name" href="#enumdef-xrmeshquality" id="ref-for-enumdef-xrmeshquality①①"><c- n>XRMeshQuality</c-></a> <a data-default="&quot;medium&quot;" data-type="XRMeshQuality " href="#dom-xrworldmeshfeature-quality"><code><c- g>quality</c-></code></a> = "medium";
    <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-double" id="ref-for-idl-double③"><c- b>double</c-></a> <a data-default="10.0" data-type="double " href="#dom-xrworldmeshfeature-width"><code><c- g>width</c-></code></a> = 10.0;
    <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-double" id="ref-for-idl-double①①"><c- b>double</c-></a> <a data-default="10.0" data-type="double " href="#dom-xrworldmeshfeature-height"><code><c- g>height</c-></code></a> = 10.0;
    <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-double" id="ref-for-idl-double②①"><c- b>double</c-></a> <a data-default="10.0" data-type="double " href="#dom-xrworldmeshfeature-breadth"><code><c- g>breadth</c-></code></a> = 10.0;
};

<c- b>dictionary</c-> <a href="#dictdef-xrnearmeshfeature"><code><c- g>XRNearMeshFeature</c-></code></a>: <a class="n" data-link-type="idl-name"><c- n>XRFeatureInit</c-></a> {
    <a class="n" data-link-type="idl-name" href="#enumdef-xrmeshquality" id="ref-for-enumdef-xrmeshquality②①"><c- n>XRMeshQuality</c-></a> <a data-default="&quot;medium&quot;" data-type="XRMeshQuality " href="#dom-xrnearmeshfeature-quality"><code><c- g>quality</c-></code></a> = "medium";
};

<c- b>dictionary</c-> <a href="#dictdef-xrmeshblock"><code><c- g>XRMeshBlock</c-></code></a> {
    <c- b>required</c-> <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-Float32Array" id="ref-for-idl-Float32Array②"><c- b>Float32Array</c-></a> <a data-type="Float32Array " href="#dom-xrmeshblock-vertices"><code><c- g>vertices</c-></code></a>;
    <c- b>required</c-> <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-Uint16Array" id="ref-for-idl-Uint16Array①"><c- b>Uint16Array</c-></a> <a data-type="Uint16Array " href="#dom-xrmeshblock-indices"><code><c- g>indices</c-></code></a>;
    <a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-Float32Array" id="ref-for-idl-Float32Array①①"><c- b>Float32Array</c-></a> <a data-type="Float32Array " href="#dom-xrmeshblock-normals"><code><c- g>normals</c-></code></a>;
};

<c- b>interface</c-> <a href="#xrnearmesh"><code><c- g>XRNearMesh</c-></code></a> {
    <c- b>readonly</c-> <c- b>setlike</c->&lt;<a class="n" data-link-type="idl-name" href="#dictdef-xrmeshblock" id="ref-for-dictdef-xrmeshblock②①"><c- n>XRMeshBlock</c-></a>>;
};

<c- b>interface</c-> <a href="#xrworldmesh"><code><c- g>XRWorldMesh</c-></code></a> {
    <c- b>readonly</c-> <c- b>maplike</c->&lt;<a class="idl-code" data-link-type="interface" href="https://heycam.github.io/webidl/#idl-DOMString" id="ref-for-idl-DOMString①"><c- b>DOMString</c-></a>, <a class="n" data-link-type="idl-name" href="#dictdef-xrmeshblock" id="ref-for-dictdef-xrmeshblock③①"><c- n>XRMeshBlock</c-></a>>;
};

<c- b>dictionary</c-> <a href="#dictdef-xrmetadata"><code><c- g>XRMetadata</c-></code></a> {
    <a class="n" data-link-type="idl-name" href="#xrworldmesh" id="ref-for-xrworldmesh①"><c- n>XRWorldMesh</c-></a> <a class="idl-code" data-link-type="dict-member" data-type="XRWorldMesh " href="#dom-xrmetadata-worldmesh" id="ref-for-dom-xrmetadata-worldmesh①"><c- g>worldMesh</c-></a>;
    <a class="n" data-link-type="idl-name" href="#xrnearmesh" id="ref-for-xrnearmesh①"><c- n>XRNearMesh</c-></a> <a class="idl-code" data-link-type="dict-member" data-type="XRNearMesh " href="#dom-xrmetadata-nearmesh" id="ref-for-dom-xrmetadata-nearmesh①"><c- g>nearMesh</c-></a>;
};

<c- b>partial</c-> <c- b>interface</c-> <a class="idl-code" data-link-type="interface"><c- g>XRFrame</c-></a> {
    <c- b>readonly</c-> <c- b>attribute</c-> <a class="n" data-link-type="idl-name" href="#dictdef-xrmetadata" id="ref-for-dictdef-xrmetadata①"><c- n>XRMetadata</c-></a> <a data-readonly data-type="XRMetadata" href="#dom-xrframe-metadata"><code><c- g>metaData</c-></code></a>;
};

</pre>
  <h2 class="no-num no-ref heading settled" id="issues-index"><span class="content">Issues Index</span><a class="self-link" href="#issues-index"></a></h2>
  <div style="counter-reset:issue">
   <div class="issue"> should the world mesh follow the observer or should it stay relative to the original position or should it be configurable?<a href="#issue-d4b98141"> ↵ </a></div>
   <div class="issue"> should the world mesh have an XRSpace?<a href="#issue-15434211"> ↵ </a></div>
   <div class="issue"> should the near mesh have an XRSpace?<a href="#issue-a32157e9"> ↵ </a></div>
   <div class="issue"> is <a class="property" data-link-type="propdesc">normals</a> needed? If so, should it be requested during initialisation?<a href="#issue-27e155ec"> ↵ </a></div>
   <div class="issue"> should the mesh data persist per browser session or per xr session?<a href="#issue-ffb06508"> ↵ </a></div>
   <div class="issue"> clarify this section<a href="#issue-22eb3e63"> ↵ </a></div>
  </div>
  <aside class="dfn-panel" data-for="enumdef-xrmeshquality">
   <b><a href="#enumdef-xrmeshquality">#enumdef-xrmeshquality</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-enumdef-xrmeshquality">2.1. XRMeshQuality</a>
    <li><a href="#ref-for-enumdef-xrmeshquality①">2.2. XRWorldMeshFeature</a>
    <li><a href="#ref-for-enumdef-xrmeshquality②">2.3. XRNearMeshFeature</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="dictdef-xrmeshblock">
   <b><a href="#dictdef-xrmeshblock">#dictdef-xrmeshblock</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-dictdef-xrmeshblock">3.1. XRMesh structures</a> <a href="#ref-for-dictdef-xrmeshblock①">(2)</a> <a href="#ref-for-dictdef-xrmeshblock②">(3)</a> <a href="#ref-for-dictdef-xrmeshblock③">(4)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="dom-xrmeshblock-vertices">
   <b><a href="#dom-xrmeshblock-vertices">#dom-xrmeshblock-vertices</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-dom-xrmeshblock-vertices">3.1. XRMesh structures</a> <a href="#ref-for-dom-xrmeshblock-vertices①">(2)</a> <a href="#ref-for-dom-xrmeshblock-vertices②">(3)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="dom-xrmeshblock-indices">
   <b><a href="#dom-xrmeshblock-indices">#dom-xrmeshblock-indices</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-dom-xrmeshblock-indices">3.1. XRMesh structures</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="dom-xrmeshblock-normals">
   <b><a href="#dom-xrmeshblock-normals">#dom-xrmeshblock-normals</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-dom-xrmeshblock-normals">3.1. XRMesh structures</a> <a href="#ref-for-dom-xrmeshblock-normals①">(2)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="xrnearmesh">
   <b><a href="#xrnearmesh">#xrnearmesh</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-xrnearmesh">3.1. XRMesh structures</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="xrworldmesh">
   <b><a href="#xrworldmesh">#xrworldmesh</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-xrworldmesh">3.1. XRMesh structures</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="dictdef-xrmetadata">
   <b><a href="#dictdef-xrmetadata">#dictdef-xrmetadata</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-dictdef-xrmetadata">3.2. XRFrame</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="dom-xrmetadata-worldmesh">
   <b><a href="#dom-xrmetadata-worldmesh">#dom-xrmetadata-worldmesh</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-dom-xrmetadata-worldmesh">3.1. XRMesh structures</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="dom-xrmetadata-nearmesh">
   <b><a href="#dom-xrmetadata-nearmesh">#dom-xrmetadata-nearmesh</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-dom-xrmetadata-nearmesh">3.1. XRMesh structures</a>
   </ul>
  </aside>
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